Such transmissions are known, for example, from WO 2012/052284 A1. In WO 2012/052284 A1, a multi-speed transmission with six forward gears and one reverse gear is shown, which comprises four planetary gear sets, seven rotatable shafts and five shift elements, whereas the sun gear of the first planetary gear set is connected to the sixth shaft, which is attachable through a first brake to the housing of the transmission, whereas the bar of the first planetary gear set is connected to the fifth shaft, which is connected to the sun gear of the second planetary gear set and is attachable through a second brake to the housing, whereas the drive shaft is connected to the ring gear of the first planetary gear set and to the sun gear of the third planetary gear set and is detachably connectable through a clutch to the seventh shaft connected to the bar of the third planetary gear set and the ring gear of the fourth planetary gear set, whereas the fourth shaft is connected to the ring gear of the third planetary gear set and to the bar of the second planetary gear set and is connectable through a third brake to the housing, whereas the output shaft is connected to the ring gear of the second planetary gear set and to the bar of the fourth planetary gear set and whereas the sun gear of the fourth planetary gear set is connected to the third shaft, which is attachable through a fourth brake to the housing.
The disadvantage here is that internal shift elements, such as multi-disk clutches or brakes, are hydraulically actuated. This hydraulic actuation leads to high hydraulic losses. In order to avoid such actuation losses, providing electro-mechanical or electro-hydraulic actuation has been proposed. In turn, the disadvantage here is that the shift elements, primarily clutches, are difficult to access, in particular if good gearing efficiency and low component stresses with low construction costs are desired.